Conversion of hydrocarbon oils



CONVERSION OF HYDROCARBON OILS Filed Aug. 17, 1935 C OZ 1772 72 furnaceFurnace 40 Patented Nov. 30, 1937 UNITED STATES EATENT OFFICE Jacob B.Heid, Chicago,

Ill., assignor to Universal l@il Products Company, Chicago, Ill., acorporation of Delaware Application August 17, 1935, Serial No. 36,616

5 Claims.

This invention particularly refers to an improved process for theconversion of hydrocarbon oils to produce primarily high yields ofdesirable light distillate such as motor fuel of good antiknock valueand good quality liquid residue'.

In the present process the charging stock is subjected to relativelymild conversion, desirable light distillate recovered from the resultingproducts b-y fractionation and condensation and the remaining higherboiling products separated into intermediate fractions (reux condensate)and residual liquid, the residual liquid subjected to a relatively mildcracking or viscosity breaking operation and introduced into avaporizing chamber, the intermediate fractions subjected to more severeconversion conditions in a separate heating coil and communicatingreaction chamber, the resulting liquid conversion products subjected tofurther vaporization in said vaporizing chamber, the vaporous productsfrom: the last mentioned cracking operation subjected to fractionationtogether with the vaporous products from said vaporizing chamber, thereilux condensate resulting from the last mentioned fractionating stepreturned to the last mentioned cracking stage for further conversion andfractionated vapors of the desired end-boiling point subjected tocondensation for the recovery of the desired light distillate product.

The accompanying diagrammatic drawing illustrates one specific form. ofapparatus embodying the features of the present invention.

Referring to the drawing, hydrocarbon` oil charging stock for theprocess, which may be any desired type of oil but is normally an oil ofrelatively wide boiling range or of relatively highboilingcharacteristics, is supplied through line I and Valve 2 to pump 3 bymeans of which it is fed through line l and valve E into heating coil E.The charging stock may, of course, be preheated, when desired, in anywell known manner not illustrated, prior to its introduction into theheating coil.

A furnace l of any desired form supplies the required heat to the oilpassing through heating coil ii to subject the same to the desiredconversion temperature, preferably at a substantial superatmosphericpressure and the heated products are discharged from the heating coilthrough line 8 and Valve 9 into separating chamber Il).

Chamber i is preferably operated at a substantially reduced pressurerelative to that employed in heating coil 6 but may, when desired, beoperated at substantially the same pressure as that employed in theoutlet from the heating coil.

Separation of Vaporous and liquid conversion products is accomplished inchamber IIJ, the latter being withdrawn from the lower portion of thiszone through line l! and valve I2 to pump I3 by means of which it issupplied through line Ill and valve I5 to heating coil I6 for furthertreatment, as will be later more fully described.

In the case here illustrated separating chamber lil comprises the lowerportion of column I'I, the upper portion of which comprises fractionatorI8, and the vaporous conversion products from chamber it pass through asuitable partition I9 into the iractionator wherein their componentsboiling above the range of the desired light distillate product of thisstage of the process are condensed as reflux condensate.

Fractionated vapors of the desired end-boiling point are Withdrawn,together with uncondensable gas produced by the operation, from theupper portion of fractionator I8 through line 20 and may be directedthrough Valve 2| in this line to condensation and cooling in condenser22. 'Ihe resulting distillate and gas passes through line 23 and valve2li to collection and separation in receiver 25. Uncondensable gas. maybe released from the receiver through line 26 and Valve 2'I. Distillatemay be withdrawn from' receiver 25 through line 28 and valve 29 tostorage or to any desired further treatment. When desired, a regulatedportion of the distillate collected in receiver 25 may be recirculatedby well known means, not shown in the drawing, to the upper portion offractionator I3 to serve as a coolingand reuxing medium in this zone.

The reuX condensate formed in fractionator I8 may be Withdrawn from thelower portion of this zone through line 33 and valve 34 to pump 35 bymeans of which it is supplied through line 36, valve 31 and line 38 toheating coil 39 for further conversion.

Heating coil 39 is located within a furnace 4I) of any suitable form bymeans of which the oil supplied to this Zone is subjected to the desiredbe withdrawn in commingled state fromv the lower portion of chamber 43and directed through line 44 and valve 45 into reduced pressurevaporizing chamber 45. However, when desired, separation of the vaporousproducts and liquid conversion products may be accomplished in thereaction chamber, in which case the liquid conversion products may bedirected to chamber 46, in the manner previously described, either aloneor together with a regulated portion of the vaporous products from thereaction chamber, while the total or the remaining portion of thevaporous products are separately removed from any suitable point abovethe point of removal of the liquid conversion products and in the casehere illustrated are directed through line 4l, valve 48 and line 49 tofractionation in fractionator 59, although the vaporous products fromchamber 43 may, when desired, be introduced, all or in part, by wellknown means not illustrated, into chamber 46.

Heating coil i6 is supplied with the required heat from a furnace 5I ofany suitable form by means of which the liquid conversion products fromchamber H3 are subjected to relatively mild conversion or viscositybreaking under the desired conversion conditions of elevated temperatureand superatmospheric pressure, the heated products being discharged fromheating coil l5 through line 52 and valve 53 into vaporizing chamber 46.

Chamber 46 is preferably maintained at a substantially reduced pressurerelative to that employed in reaction chamber 43 by means of whichfurther vaporization of the liquid conversion products supplied to thiszone from the reaction chamber is accomplished. Separation of vaporousand residual liquid components of the heated products supplied to thiszone from heating coil i6 is also accomplished in chamber 45. Theresidual liquid remaining unvaporized in this zone is withdrawn from thelower portion thereof through line 54- and valve 55 to cooling andstorage or elsewhere, as desired. The vaporous conversion productssupplied to chamber 40 and the vapors evolved in this Zone are withdrawnfrom the upper portion thereof through line 5S and valve 51 and aredirected through line 49 to fractionation in fractionator 59.

The components of the vaporous products supplied to fractionator 59boiling above the range of the desired final light distillate productare condensed in this Zone as reflux condensate. The reiiux condensateis removed from the lower portion of the fractionator through line 60and valve 5| to pump Si. by means of which it is returned through line03, valve 54 and line 38 to further conversion in heating coil 39together with the reflux condensate from fractionator I8, which issupplied to this zone in the manner previously described.

Fractionated vapors of the desired end-boiling point are withdrawn fromthe upper portion of fractionator 59 through line 65 and valve S6 andare subjected to condensation and cooling in condenser 5'5. Theresulting distillate and gas passes through line 5S and valve 5S tocollection and separation in receiver l0. Uncondensable gas may bereleased from the receiver through line 'H and valve '12. Distillate maybe withdrawn from receiver 'i9 through line 73 and valve i4 to storageor to any desired further treatment. When desired, a regulated portionof the distillate collected in receiver lil may be recirculated by wellknown means, not shown in the drawing, to the upper portion offractionator 59 to serve as a cooling and refluxing medium in this zone.

In a process such as illustrated and above described, the preferredoperating conditions may be approximately as follows: The heating coilto which the charging stock is supplied may utilize an outlet conversiontemperature ranging, for example, from 800 to 950 F., or thereabouts,preferably with a superatmospheric pressure at this point in the systemof from to 500 pounds, or thereabouts, per square inch. The succeedingseparating chamber is preferably operated at a substantially reducedpressure relative to that employed in the heating coil although, whendesired, this zone may be operated at a substantial superatmosphericpressure up to approximately the same as that employed in the heatingcoil. The fractionating, condensing and collecting equipment of thisstage of the system may be operated at substantially the same orsomewhat lower pressures than that employed in the separating chamber.The heating coil to which the reflux condensates from both fractionatorsof the system is supplied may utilize a conversion temperature, measuredat the outlet therefrom, ranging, for example, from 850 to 975 F., orthereabouts, preferably with a superatmospheric pressure at this pointin the system of from 100 to 500 pounds or more per square inch. Asubstantial superatmospheric pressure substantially the same as thatemployed in the reflux heating coil or somewhat reduced relative theretomay be utilized in the succeeding reaction chamber. The heating coil towhich liquid conversion products resulting from said relatively mildconversion of the charging stock are supplied for further conversion orViscosity breaking may utilize an outlet temperature ranging, forexample, from 'Z50 to 900 F., preferably with a superatmosphericpressure at this point in the system of from 100 to 500 pounds, or more,per square inch. The vaporizing chamber is preferably operated, aspreviously mentioned, at a substantially reduced pressure relative tothat employed in the reaction chamber ranging, for example, from 100pounds, or thereabouts, per square inch down to substantiallyatmospheric pressure. The pressure employed in the Vaporizing chambermay be substantially equalized or somewhat reduced in the succeedingfractionating, condensing and collecting portions of the system.

As a specific example of the operation of the process of the presentinvention, charging stock `comprising a Mid-Continent topped crude ofabout 26 A. P. I. gravity is subjected in the first heating coil of thesystem to an outlet conversion temperature of approximately 900 F. at asuperatmospheric pressure of about 250 pounds per square inch and theheated products are introduced into a separating chamber operated at asuperatmospheric pressure of about 50 pounds per square inch. Liquidconversion products are withdrawn from the separating chamber, subjectedto a viscosity breaking operation in a separate heating coil employingan outlet conversion temperature of approximately 825 F. and asuperatmospheric pressure of about 200 pounds per square inch, theheated products being introduced into a vaporizing chamber operated at asuperatmospheric pressure of about 50 pounds per square inch. Adistillate of about 350 F. end-boiling point is recovered as the motorfuel product of the first cracking stage and the intermediate fractions(reflux condensate) are subjected in a separate heating coil to anoutlet conversion temperature of approximately 940 F. at asuperatmospheric pressure of approximately 350 pounds per square inch.'I'he heated products from the last mentioned heating coil areintroduced into a reaction chamber operated at substantially the samepressure and both vaporous and liquid products from this zone aresupplied to said vaporizing chamber. The vaporous products from thevaporizing chamber are subjected to fractionation at substantially thesame pressure as that employed in the vaporizing chamber, the resultingreflux condensate being returned to the last mentioned heating coil forfurther conversion and a motor fuel product of about 400 F. end-boilingpoint being recovered by condensation of the fractionated vapors. Thisoperation will produce, per barrel of charging stock, approximately 59per cent of motor fuel of good antiknock value and about 32 per cent ofheavy liquid residue meeting market specifications for premium fuel oil,the remainder being chargeable, principally, to uncondensable gas.

I claim as my invention:

l. A process for the conversion of hydrocarbon oils which comprisessubjecting hydrocarbon oil charging stock containing intermediate andresidual portions of petroleum to conversion conditions of crackingtemperature and superatmospheric pressure in a first cracking stage,separating the resulting vaporous and liquid conversion products,subjecting the vapors to fractionation whereby their insufficientlyconverted components are condensed as reflux condensate, recovering adesirable light distillate from the fractionated vapors by condensation,subjecting the reflux condensate to independently controlled conversionconditions of superatmospheric pressure and relatively highertemperature in a second cracking stage of the same system, separatingthe resulting vaporous and liquid conversion products, subjecting thelatter to further vaporization at substantially reduced pressurerelative to that at which they are produced, subjecting said liquidconversion products from the first cracking stage to further relativelymild conversion at cracking temperature and superatmospheric pressurefor the purpose of materially re'- ducing their viscosity, therebyforming additional vaporous and liquid conversion products, comminglin'gthe latter with the nonvaporous conversion products from said secondcracking stage and recovering the commingled residual liquids,subjecting the vaporous products from said viscosity reducing operationand from said second cracking stage to fractionation for the formationof reflux condensate, returning the latter to said second cracking stagefor further conversion, subjecting fractionated vapors of the desiredend-boiling point from the last mentioned fractionating step tocondensation, and recovering the resulting distillate.

2, A process for the conversion of hydrocarbon oils which comprisessubjecting hydrocarbon charging stock containing intermediate andresdual portions of petroleum to conversion conditions of crackingtemperature and superatmospheric pressure in a heating coil, separatingthe resulting vaporous and liquid conversion products, subjecting thevapors to fractionation for the formation of reflux condensate and therecovery of desirable light distillate from the fractionated vapors bycondensation, subjecting the reflux condensate to conversion conditionsof superatmospheric pressure and relatively higher temperature in aseparate heating coil and communicating reaction chamber, separating theresulting vaporous and liquid conversion products, subjecting the latterto further vaporization in a reduced pressure vaporizing chamber,subjecting said residual liquid from the rst mentioned cracking stage tocontinued relatively mild conversion at cracking temperature andsuperatmospheric pressure in a separate heating coil to reduce theviscosity thereof, introducing the heated products from said separateheating coil into said vaporizing chamber, withdrawing non-vaporousresidual liquid from the vaporizing chamber, subjecting vaporousproducts from the vaporizing chamber to fractionation for the formationof reflux condensate, returning said reflux condensate for furtherconversion to the same heating coil to Which the reflux condensate fromthe first mentioned cracking stage is supplied, subjecting fractionatedvapors of the desired end-boiling point from the last mentionedfractionating stage to condensation, and recovering the resultingdistillate.

3. A process as claimed in claim 2 wherein both vaporous and liquidconversion products are withdrawn in commingled state from said reactionchamber and introduced into said vaporizing chamber.

4. A process as claimed in claim 2 wherein vaporous and residual liquidconversion products are separated in said reaction chamber, the lattersupplied therefrom to said vaporizing chamber and vaporous productsseparately Withdrawn from the reaction chamber and supplied to the lastmentioned fractionating stage.

5. A process for producing motor fuel and good quality liquid residuefrom hydrocarbon charging stock containing intermediate and residualportions of petroleum, which comprises heating said charging stock tocracking temperature under pressure in a heating coil and separating thesame into vapors and liquid, subjecting fractions of the vapors heavierthan gasoline to more drastic cracking conditions than the chargingstock in a second heating coil and subsequently separating the same intovapors and unvaporized oil, subjecting said liquid in a third heatingcoil to relatively mild conversion conditions of a viscosity reducingcharacter and then separating vapors therefrom, combining the remainingunvaporized portion of said liquid with said unvaporized oil andrecovering the resultant liquid mixture as a product of the process,introducing the last-named vapors and the second-mentioned vapors to afractionating zone and fractionating the same therein in admixture,supplying resultant reflux condensate from the fractionating Zone tosaid second coil for drastic cracking therein together with saidfractions heavier than gasoline, and finally condensing and collectingthe vapors uncondc-nsed in the fractionating zone.

JACOB B. HEID.

